Steep Cliffs on Mars . ... Mars Express , DLR , ESA Explanation: Vertical cliffs of nearly two kilometers occur near the North Pole of Mars. ... The cliffs are thought to border volcanic caldera . Although the sheer drop of the Martian cliffs is extreme, the drop is not as deep as other areas in our Solar System , including the 3.4-kilometer depth of Colca Canyon on Earth and the 20 kilometer depth of Verona Rupes on Uranus' moon Miranda . ... NASA Web Site Statements, Warnings, and Disclaimers . ...